Method for the manufacture of beryllium and alloys



Patented N... 26, 1935 UNITED STATES 2,022,404 METHOD FOR THEMANUFACTURE OF BERYLLIUM AND ALLOYS Harry G. Claflin, Marysville, Mich,assignor to The Beryllium Corporation,

New York, N. Y.,

a corporation of Delaware No Drawing.

Application June 26, 1934, Serial No. 732,436

8 Claims. (01. 204-19) This invention relates to a method for theconvenient and economical manufacture of beryllium. It is useful in theproduction of elementary beryllium and may effectively .be employed aspart of a process for the production or continuous production of alloysof beryllium.

Themarliest methods for the isolation of beryllium were thermal innature, the alkali metals being used to reduce berylliumhalides, such asthe chloride or the double alkali beryllium fluoride. Later,electrolytic eiforts hinged around the decomposition of the alkaliberyllium fluorides, such as NazBeF4; in more recent times, electrolyticoperations have centered about double fluoride mixtures higher inberyllium content, such as NaF.2BeFz, and about the anhydrous BeClz. Thelast mentioned has one great advantage over all other materials hithertosuggested as initial material for electrolytic operations: It permitsthere is nothing to build up in the electrolytic bath; fulldecomposition of the added substance, BeCln, occurs, and the bathreturns to its original state, ready for further additions of theelectrolyzable substance. However, anhydrous BeCl: is quitediflicult-and costly of manufacture, requiring the heating of normalberyllium compounds in the. simultaneous presence of chlorinating andreducing agents; this has made its use on a commercial scale quiteexpensive,-though technically it is admirable in most respects.

As for the fluorine compounds of beryllium, when combined with alkalifluorides in molecular compounds they have beenfar easier and lessexpensive to manufacture, but they sufier from the fact that continuousoperation is impossible. Addition of NazBeF to an electrolysis bath, forexample, results in the release pf Be at the cathode and half of thetotal added fluorine at the anode, but there is meanwhile a continuousbuild ing up of NaF in increasing amount of NaF in the bath makescontinued operation impossible.

Moreover, NazBeFl is too low in tent to yield well-operatingelectrolytic such baths are too easily subject to anode effect",particularly when in association with any excess NaF over that presentin the NaaBeFi itseli.

, Pure BeFz, while theoretically far more desirable than any doublefluoride-since, like BeClz, it would leave nothing in the bath afterelectrolysis of the beryllium content-has hitherto been practicallyunknown as a chemical entity, because of beryllium conof continuousoperation, since that the double point of beryllium the bath.- SoOner orlater, the

baths;

at all in normal operation.

great idifliculties in its isolation. Evaporation of an aqueous solutioncontaining only BeFz leaves nothing but a gummy basic mixture(frequently termed the oxyfluoride) even repeated evaporation withexcess HF merely changesthe ratio of 5 basicity; fluorinecontent.

Aside from direct union of beryllium and fluorine, and reaction of dryHF on beryllium metal, there has hitherto been known only one procedurefor making pure BeF2-thermal decomposition of the double ammoniumberyllium fluoride, in accordance with the reaction:

Experience with the of beryllium fluoride in elecfluoride as a sourcetrolyses has hitherto been quite discouraging and devoid of hopeiulness.And, because of the previous failure, under the conditions tried, ofthis double ammonium beryllium fluoride as a source of electrolyzablematerial,-it has been assumed that no'convenient method exists for,utilizing BeFz as electrolytic material.

Contrary to all such past beliefs, I have found ammonium berylliumfluoride, properly used, offers an almost ideal source of electrolyzableberyllium. In the past, the additions, for the most part, of ammoniumberyllium fluoride have been to baths predominant in alkali earthfluorides, with high operating temv peraturesspecifically, at or abovethe melting (1280" 0.). Under the conditions of such high temperatureoperation, various factors appear as interference, among them reactionbetween the liberated ammonia (NH4F=NHa+I-IF) and the metallicberyllium.

I have found that, in electrolytic operations held below the meltingpoint of beryllium" and preferably below 1000 C. (with the metalconsequently appearing as flakes or spangles instead of as a moltenregulus) the direct addition of ammonium beryllium fluoride does notcause such undesired reactions. I find that, by adding this compound toa bath preferably of sodium or other alkali fluoride, decomposition ofthe double compound takes place; and, as a result, there is formed inthe batlea mutually soluble mixture of the alkali fluoride and berylliumfluoride, which can be varied in the matter of ratio of components, asdesired. In this way, the proportion of BeFz in the bath can be raisedsufliciently above the point where anode effect objectionably sets in sothat this unhappy factor does not present itself The ammonium berylliumfluoride should be slowly added to the fused bath to avoid objectionableagitation.

Instead of using a single alkali fluoride as the preliminary operatingfusion bath, I can use equally well, mixtures of the alkali fluorides,as well as mixtures of these with alkaline earth fluorides. Indeed, anysingle fluoride or mixture of fluorides more electropositive thanberyllium will do for the purpose. The only requirement is that thefusion bath be freely fluid and electrolyzable at a temperature belowthe melting point of beryllium. For reasons of convenience and comfortof operation, I prefer to operate with the alkali fluorides, whichpermit electrolysis to proceed smoothly in the 600 C.-800 C. range.

This invention works particularly well in conjunction with theelectrolytic process divulged in application of J. B. Arnold and myself,Serial No. 732,435, flled June 26, 1934, for the manufacture of alloysof beryllium with heavier metalssuch as copper, wherein massive metalcathodes are employed. In such use, higher temperatures are usuallyneeded say from 900 C. to 1000 C. in the case of copper. When used withmassive copper cathodes, for example, the inventions of appli-' cationSerial No. 732,435 and of this application, yield a continuous flow ofliquid copper-beryllium alloy of about 2% to about 6% beryllium content.

Having described my invention, I claim:-

1. In the electrolytic production of beryllium, the steps of addingammonium beryllium fluoride to a fusion of the fluorides of one or moremetals more electropositive than beryllium, and of electrolyzing atatemperature below the melting point of beryllium.

2. The process of obtaining elementary beryllium which includes thesteps of adding ammonium beryllium fluoride to a fusion of the fluoridesof one or more metals more electropositive than beryllium, andsubjecting the mixed fusion to electrolysis at a temperature below themelting point of beryllium.

3. In the electrolytic production of beryllium, the steps of addingammonimn beryllium fluoride to a bath of a fluoride of one or moremetals 5 more electropositive than beryllium, and of electrolyzing at atemperature below the melting point of beryllium.

4.In the electrolytic production of beryllium, the steps of addingammonium beryllium fluoride 10 to a bath of a fluoride of one or moremetals more electropositive than beryllium, and of electrolysing at atemperature below the melting point of beryllium, and preferablybelow1000 C.

5. The process of forming fused mixtures of 15 beryllium fluoride andthe fluorides of one or. more metals more electropositive than berylliumwhich includes the steps of slowly or gradually adding ammoniumberyllium fluoride to a fusion of the other fluoride or fluorides and ofholding 20 the temperature below the melting point of beryllium.

6. The process of forming fused mixtures of beryllium fluoride and thefluorides of one or more alkali metals which includes the steps of 25slowly or gradually adding ammonium beryllium fluoride to a fusion ofthe alkali fluoride or fluorides, and of holding the temperature belowthe melting point ofberyllium.

7. The process of forming fused mixtures of 30 beryllium fluoride andsodium fluoride which includes the steps of slowly or gradually addingammonium beryllium fluoride to a fusion of sodium fluoride and ofholding the temperature below the melting point of beryllium.

8. In the electrolytic production of beryllium, the steps of addingammonium beryllium fluoride to a fusion of the fluorides of one or morealkali metals, and of electrolyzing at a temperature below the meltingpoint of beryllium.

40 HARRY C. CLAFLIN.

